Comment 4 for bug 901790

ok so after some test i can say that nautilus & marlin works fine, u can try them with adwaita the default gnome theme or zukini. Ambiance is just incomplete.

At the start of gtk-3.0/gtk-widgets.css you'll find the different states, most of them are empty on Ambiance which is why we got an awfull visual on nautilus or marlin, we even got selections dissapearing after a right click menu or once our widow lost focus.

You can complete ambiance themes by replacing the section containing the states with:

-----------------------
*:active {
 background-color: shade (@bg_color, 0.915);
}

*:active:hover:insensitive {
}

*:active:insensitive {
}

*:hover {
 background-color: shade (@bg_color, 1.02);
}

*:hover:insensitive {
}

*:selected {
 background-color: @selected_bg_color;
 color: @selected_fg_color;
}

*:selected:focused {
 background-color: @selected_bg_color;
 color: @selected_fg_color;
}

--------------------------
you can theme specifically the views by using .view.cell:STATE where STATE is selected/hover/focused etc...
you can specifically theme marlin icon views by using ExoIconView.view.Cell:STATE

Hope it helps.
This bug is officially invalid.